An electronic apparatus that forms the mobile phone or the mobile terminal may include a main part, and a sub part that is slideable with respect to the main part. The main part may include a ten-key, a microphone, or the like, and the sub part may include a liquid crystal display, speaker, or the like.
In the case of the electronic apparatus forming the mobile phone, a sliding operation may be carried out by a user to slide the sub part that is attached to the main part via a slide unit for the electronic apparatus, in order to select an open state in which the speaker is positioned at the user's ear and the microphone is positioned near the user's mouth or jaw. Similarly, in the case of the mobile terminal, a closed state in which the ten-key is covered by the sub part may be selected when the mobile terminal is not in use, and an open state in which the ten-key or the liquid crystal display is exposed to the front may be selected when using the mobile terminal.
Compared to a hinge mechanism, the slide unit for the electronic apparatus may enable the sub part to be easily opened and closed with respect to the main part by sliding the sub part with respect to the main part using a single hand. In addition, the hinge mechanism may require a certain space, extending radially outwards from a center axis of the hinge mechanism, in order to enable rotation of the sub part with respect to the main part via the hinge mechanism when opening and closing the sub part with respect to the main part, however, the slide unit does not require such a space. Hence, the user may easily carry out the sliding operation to open and close the sub part with respect to the main part, without requiring much space.
The above type of electronic apparatus is described in a Patent Document 1. The slide unit for the electronic apparatus illustrated in the Patent Document 1 includes a slide plate fixed to the sub part, a plate-shaped base fixed to the main part, and guide rails provided on the base and slideably engaging the slide plate.
In addition, the slide plate is attached to the base via a spring whose direction of urging force reverses at an intermediate point of a stroke thereof. Hence, the urging force acts as a reaction force with respect to the user's operation in a first half of the sliding operation in the opening direction, and acts as an assisting force with respect to the user's operation in a second half. Because the urging force of the spring acts as the reaction force and the assisting force, the operability for the user may be improved by requiring the operating force of the user substantially only during the first half of the sliding operation.
The sliding unit may be used in an electronic apparatus having a rectangular parallelepiped shape with a bottom surface that is elongated in a horizontal direction. In the case in which the sub part is configured to slide in a vertical direction with respect to the main part, it may be preferable to minimize an amount of overlap between sub part and the main part in a state in which the sub part is slid open in the vertical direction.
Particularly in the case of the electronic apparatus described above, the main part may include an input device such as the ten-key, a keyboard, or the like. Hence, from the point of view of enabling easy user operation of the input device, it may be preferable to increase the exposed area of the main part in the open state in which the sub part is slid open. In other words, in the open state in which the sub part is slid open in a sliding direction, it may be preferable to minimize the amount of overlap between the sub part and the main part in the sliding direction, in order to maximize the exposed area of the main part in the open state. That is, it may be preferable to minimize the area of the main part hidden by the sub part due to the overlap.
However, the stability of the sub part and the rigidity of parts of the slide plate and the guide rail slideably catching each other need to be maintained when the user operates the sub part in the open state. Hence, it may also be preferable to extend the slideably catching length of the slide plate and the guide rail that slideably catch each other to a certain extent. In other words, from the point of view of the above stability and rigidity, it may be preferable to provide a certain amount of overlap between the sub part and the main part in the open state of the sub part.